Spatio-temporal differences in perineuronal net expression in the mouse hippocampus, with reference to parvalbumin

Area of Science:

• Neuroscience
• Extracellular Matrix Biology

Background:

• Perineuronal nets (PNNs) are extracellular matrix aggregates regulating neuronal circuit plasticity.
• PNNs are closely associated with parvalbumin (PV)-containing GABAergic neurons.

Purpose of the Study:

• To investigate spatial and temporal PNN intensity variations in the mouse hippocampus.
• To compare PNN changes with PV intensity during development and aging.

Main Methods:

• Quantification of Wisteria floribunda agglutinin (WFA)-labeled PNN intensity in single hippocampal cells.
• Assessment of parvalbumin (PV) intensity in the same cells.
• Analysis of PNN and PV intensity across different hippocampal regions, ages, and dorsoventral axes.

Main Results:

• PNN intensity was low and uniform in young mice, increasing developmentally, with greater increases dorsally.
• Adult mice exhibited higher PNN intensity in the dorsal hippocampus compared to the ventral.
• Aging differentially affected dorsal hippocampal PNNs (decreased in CA1, stable in CA3, increased in DG), with no significant changes ventrally. PV intensity changes did not consistently mirror PNN changes.

Conclusions:

• PNN expression is differentially regulated in dorsal and ventral hippocampal circuits during development and aging.
• These PNN variations may underlie distinct roles in cognition (dorsal) and emotion (ventral) processing.
• The relationship between PNNs and PV intensity is complex and region/age-dependent.